A prospective, randomized study of 60 patients undergoing sialography was conducted to compare Lipiodol Ultra Fluid (UF) (Ethyl diiodostearate, May & Baker Ltd), with Urografin 290 (meglumine diatrizoate 52.1% w/v and sodium diatrizoate 7.9% w/v, Schering). The quality of the images, the clinical tolerance and the side-effects of contrast were compared. Both agents produced adequate opacification of ducts but poor intra-gland duct filling was seen in two patients examined with Lipiodol UF. There were significantly more side-effects (which were also more severe) in the Lipiodol group. It is concluded that Urografin 290 is the better contrast agent for sialography because of better filling of intra-gland ducts and greater clinical tolerance.